Catalyst mixture for the isomerization of dichlorobutenes

ABSTRACT

The invention relates to a composition producible by mixing an aromatic amine or several aromatic amines of the general formula I,  
                 
 
     Wherein  
     R 1  to R 7 , independently of one another, denote H, C 1  to C 12  alkyl, C 5  to C 8  cycloalkyl, C 6  to C 14  aryl, alkylaryl, arylalkyl, with two adjacent groups together optionally forming saturated or unsaturated C 3  to C 14  cycles, or —SiR 8 R 9 R 10 , wherein R 8  to R 10 , independently of one another, can represent C 1  to C 4  alkyl, C 5  to C 8  cycloalkyl or C 6  to C 14  aryl,  
     with an anhydrous copper salt CuX n , wherein n=1 or 2 and X=halide, sulfate, acetate, acetylacetonate, or a mixture of two or more of these compounds in 1,4-dichloro-2-butene or 3,4-dichloro-1-butene, a process for the production thereof, its use as a catalyst and a process for the isomerization of 1,4-dichloro-2-butene to 3,4-dichloro-1-butene or vice versa using the composition according to the invention.

FIELD OF THE INVENTION

[0001] The invention relates to a composition producible by mixing anaromatic amine or several aromatic amines of the general formula I,

[0002] Wherein

[0003] R¹ to R⁷, independently of one another, denote H, C₁ to C₁₂alkyl, C₅ to C₈ cycloalkyl, C₆ to C₁₄ aryl, alkylaryl, arylalkyl, withtwo adjacent groups together optionally forming saturated or unsaturatedC₃ to C₁₄ cycles, or —SiR⁸R⁹R¹⁰, wherein R⁸ to R¹⁰, independently of oneanother, can represent C₁ to C₄ alkyl, C₅ to C₈ cycloalkyl or C₆ to C₁₄aryl,

[0004] With an anhydrous copper salt CuX_(n), wherein n=1 or 2 andX=halide, sulfate, acetate, acetylacetonate, naphthenate or a mixture oftwo or more of these copper salts in 1,4-dichloro-2-butene or3,4-dichloro-1-butene, a process for the production thereof, its use asa catalyst and a process for the isomerization of 1,4-dichloro-2-buteneto 3,4-dichloro-1-butene or vice versa using the composition accordingto the present invention.

BACKGROUND OF THE INVENTION

[0005] 3,4-Dichloro-1-butene is an important intermediate in theproduction of 2-chloroprene, which is used industrially as a monomer forthe production of polychloroprene rubber.

[0006] In the chlorination of butadiene, a mixture ofcis-1,4-dichloro-2-butene, trans-1,4-dichloro-2-butene and3,4-dichloro-1-butene, containing approximately 65% cis- andtrans-1,4-dichloro-2-butene and approximately 35% 3,4-dichloro-1-butene,is formed. These isomers are generally present in the mixture inequilibrium, the ratio being dependent on the production conditions. Forthe sake of simplicity, cis- and trans-1,4-dichloro-2-butene will bereferred to below jointly as 1,4-dichloro-2-butene. Because of thedifferent boiling points (1,4-dichloro-2-butene: 154-9° C. and3,4-dichloro-1-butene: 123° C.), this mixture can be separated bydistillation. Since only 3,4-dichloro-1-butene is suitable for theproduction of 2-chloroprene, the 1,4-dichloro-2-butene must beisomerized to 3,4-dichloro-1-butene and recycled into the process.

[0007] The conventional processes for the isomerization of1,4-dichloro-2-butene to 3,4-dichloro-1-butene or vice versa are basedon the use of suitable isomerization catalysts, which ensure a rapidadjustment of equilibrium between the isomers into 1,4-dichloro-2-buteneor 3,4-dichloro-1-butene at elevated temperatures. In most processes,metal salts of copper are used in the presence of basic additives, whichserve to increase the rates of reaction.

[0008] DE-A-21 38 790 discloses a process for the isomerization of1,4-dichloro-2-butene to 3,4-dichloro-1-butene or vice versa at 80 to160° C. using copper naphthenate, dinitrile and amide. In DE-A-21 43157, a process for the isomerization in the presence of copper salts andoxime derivatives at 80 to 160° C. is described. DE-A-22 00 780 claims aprocess containing a mixture of a copper compound and an organicphosphorus compound as catalyst. DE-A-21 07 468 discloses the use ofcopper naphthenate and nitro compounds, DE-A-21 30 488 the use of coppernaphthenate and nitroanilines. In DE-A-22 12 235, an isomerizationprocess using copper compound and urea derivative is described. DE-A-2206 971 claims the use of a mixture of copper compound (copper(II)stearate, oleate and naphthenate) and chlorine-containing anilinederivative. In U.S. Pat. No. 4,895,993, a process for isomerization inthe presence of a catalyst consisting of a copper compound and adithiocarbamate or trithiocarbonate derivative is disclosed .

[0009] Rostovshchikova et al., in Zh. Obshch. Khim. 1994, 64, 12,describes the use of triphenylphosphine or, in Kinet. Katal. 1992, 33,314, the use of different dialkyl sulfides in the presence of copperhalides for catalytic isomerization. Asatryan et al., in Arm. Khim. Zh.1988, 41, 278, investigated the action of macrocyclic polyethers orpolyethylene glycols and, in Arm. Khim. Zh. 1988, 41, 273, the influenceof benzonitrile, nitrobenzene, DMF, dimethyl sulfone or acetophenone.

[0010] A disadvantage of these processes is that the velocities oftransformation are comparatively low and a large quantity of undesirableby-products is formed.

[0011] In Arm. Khim. Zh. 1987, 40, 709, Asatryan et al. describedifferent isomerization catalysts based on halide salts of copper, ironor zinc in the presence of amine derivatives such as triethylamine,diethylamine, triethanolamine, ethylenediamine or aniline. However,Asatryan et al. describes the fact that aliphatic amines lead toisomerization catalysts which, owing to their greater nucleophilicity,display greater effectiveness than aromatic amines. The use of aliphaticamines is therefore recommended there.

[0012] Now, the object of the present invention was to find aneconomical process for the isomerization of 1,4-dichloro-2-butene to3,4-dichloro-1-butene or vice versa using a catalyst system thatguarantees high velocities of transformation and catalyzes theisomerization with reduced by-product formation.

[0013] Surprisingly, it has been found that, in a process for theisomerization of 1,4-dichloro-2-butene to 3,4-dichloro-1-butene or viceversa, wherein the process uses a composition that can be produced bymixing an aromatic amine and a copper salt, contrary to the findings ofAsatryan et al. in Arm. Khim. Zh. 1987, 40, 709, the rate ofisomerization is higher, the by-product formation is lower due to thelower basicity of the aromatic amines and thus, the process is moreeconomical.

SUMMARY OF THE INVENTION

[0014] The present invention provides a composition producible by mixingan aromatic amine or several aromatic amines of the general formula I,

[0015] Wherein

[0016] R¹ to R⁷, independently of one another, denote H, C₁ to C₁₂alkyl, C₅ to C₈ cycloalkyl, C₆ to C₁₄ aryl, alkylaryl, arylalkyl, withtwo adjacent groups together optionally forming saturated or unsaturatedC₃ to C₁₄ cycles, or —SiR⁸R⁹R¹⁰, wherein R⁸ to R¹⁰, independently of oneanother, can represent C₁ to C₄ alkyl, C₅ to C₈ cycloalkyl or C₆ to C₁₄aryl,

[0017] With an anhydrous copper salt CuX_(n), wherein n=1 or 2 andX=halide, sulfate, acetate, acetylacetonate or naphthenate, or a mixtureof two or more of these copper salts.

DETAILED DESCRIPTION OF THE INVENTION

[0018] C₁-C₁₂ alkyl means all linear or branched, saturated orunsaturated alkyl groups with 1 to 12 C atoms known to the personskilled in the art, such as methyl, ethyl, n-propyl, i-propyl, n-butyl,i-butyl, t-butyl, n-pentyl, i-pentyl, neo-pentyl, n-hexyl, i-hexyl,heptyl, octyl, nonyl, decyl, undecyl and dodecyl and the unsaturatedhomologues thereof.

[0019] C₅ to C₈ cycloalkyl means all cyclic alkyl groups with 5 to 8 Catoms known to the person skilled in the art, such as cyclopentyl,cyclohexyl, cycloheptyl, cyclooctyl and the unsaturated homologuesthereof.

[0020] C₆ to C₁₄ aryl means all aryl groups with 6 to 14 C atoms knownto the person skilled in the art, such as phenyl, naphthenyl, fluorenyl,anthracenyl and phenanthranyl.

[0021] Preferred aromatic amines are aniline, N,N-dimethylaniline,p-toluidine or mixtures of 2 or 3 of these components.

[0022] The molar ratio of the two components CuX_(n), wherein n=1 or 2and X=halide, sulfate, acetate, acetylacetonate, naphthenate, toaromatic amine is advantageously in the range of 1:0.5 to 1.5,preferably 1:0.7 to 1:1. The concentration of the two components isadvantageously in the range of 10⁻³ to 1 mol/l, preferably between5×10⁻² to 5×10⁻¹ mol Cu/l.

[0023] The present invention further relates to a process for theproduction of a composition according to the present invention, whereinthe components are mixed in the order: aromatic amine or amines and thenthe anhydrous copper salt or salts. It is advantageous to perform thismixing process under a protective atmosphere, such as a nitrogen orargon atmosphere, in a temperature range of 30 to 180° C., preferably 50to 150° C.

[0024] The present invention further relates to the use of thecomposition according to the present invention as a catalyst,particularly as a catalyst in a process for the isomerization of1,4-dichloro-2-butene to 3,4-dichloro-1-butene or of3,4-dichloro-1-butene to 1,4-dichloro-2-butene.

[0025] Thus, the invention further provides a process for theisomerization of 1,4-dichloro-2-butene to 3,4-dichloro-1-butene or of3,4-dichloro-1-butene to 1,4-dichloro-2-butene, wherein

[0026] a) at a temperature of 30 to 180° C., preferably in the range of50° to 150° C., an aromatic amine or several aromatic amines of thegeneral formula I,

[0027]  wherein

[0028] R¹ to R⁷, independently of one another, denote H, C₁ to C₁₂alkyl, C₅ to C₈ cycloalkyl, C₆ to C₁₄ aryl, alkylaryl, arylalkyl, withtwo adjacent groups together optionally forming saturated or unsaturatedC₃ to C₁₄ cycles, or —SiR⁸R⁹R¹⁰, wherein R⁸ to R¹⁰, independently of oneanother, can represent C₁ to C₄ alkyl, C₅ to C₈ cycloalkyl or C₆ to C₁₄aryl,

[0029] and an anhydrous copper salt CuX_(n), wherein n=1 or 2 andX=halide, sulfate, acetate, acetylacetonate, naphthenate or a mixture oftwo or more of these compounds, are added to 1,4-dichloro-2-butene,3,4-dichloro-1-butene or a mixture thereof,

[0030] b) the reaction solution is allowed to react until an equilibriumhas become established between 1,4-dichloro-2-butene and3,4-dichloro-1-butene, preferably between 1 and 180 minutes, morepreferably between 15 and 45 minutes,

[0031] c) a mixture of 1,4-dichloro-2-butene and 3,4-dichloro-1-buteneis continuously removed and this is then separated by distillation,

[0032] d) the undesirable component from the distillation performed inc) is fed back into the reaction system,

[0033] e) and optionally, simultaneously with c), 1,4-dichloro-2-buteneand/or 3,4-dichloro-1-butene is fed into the reaction system.

[0034] The process can take place, either batchwise or continuously,between 0.01 bar and 10 bar, preferably between 0.1 and 1.0 bar, itbeing recommended that a more highly concentrated solution of thecatalyst system, preferably 10⁻¹ to 1 mol Cu/l, in 1,4-dichloro-2-buteneand/or 3,4-dichloro-1-butene should first be produced and this should beadded continuously to a larger quantity of 1,4-dichloro-2-butene and/or3,4-dichloro-1-butene, so that the desired concentration, preferably5×10⁻² to 5×10⁻¹ mol Cu/l of the catalyst is obtained,1,4-dichloro-2-butene and/or 3,4-dichloro-1-butene being fed incontinuously and a mixture of 1,4-dichloro-2-butene and3,4-dichloro-1-butene being removed continuously and then separated bydistillation.

[0035] The invention is explained in more detail below, with the aid ofexamples of embodiments, without these being limited to the examples,however.

EXAMPLES

[0036] Preparation of the Catalyst Mixes

[0037] Catalyst Mix A

[0038] Under a nitrogen atmosphere, 232.0 g of 1,4-dichloro-2-butene areplaced in a 500 ml round-bottom flask with an internal thermometer,reflux condenser and pressure relief valve, 9.67 g (104 mmol) of anilineare added at 50° C. and stirring is performed at this temperature for 4h. 10.29 g (104 mmol) of copper(I) chloride are then added at 50° C. andstirring is performed at this temperature for a further 8 h.

[0039] Catalyst Mix B

[0040] 232.0 g of 1,4-dichloro-2-butene are placed in the apparatusdescribed in the production of catalyst A under nitrogen, 8.72 g (94mmol) of aniline are added at 50° C. and stirring is performed at thistemperature for 4 h. 10.29 g (104 mmol) of copper(I) chloride are thenadded at 50° C. and stirring is performed at this temperature for afurther 8 h.

[0041] Catalyst Mix C

[0042] 232.0 g of 1,4-dichloro-2-butene are placed in the apparatusdescribed in the production of catalyst A under nitrogen, 7.75 g (83mmol) of aniline are added at 50° C. and stirring is performed at thistemperature for 4 h. 10.29 g (104 mmol) of copper(I) chloride are thenadded at 50° C. and stirring is performed at this temperature for afurther 8 h.

[0043] Catalyst D

[0044] 232.0 g of 1,4-dichloro-2-butene are placed in the apparatusdescribed in the production of catalyst A under nitrogen, 6.78 g (73mmol) of aniline are added at 50° C. and stirring is performed at thistemperature for 4 h. 10.29 g (104 mmol) of copper(I) chloride are thenadded at 50° C. and stirring is performed at this temperature for afurther 8 h.

[0045] Catalyst Mix E

[0046] 232.0 g of 1,4-dichloro-2-butene are placed in the apparatusdescribed in the production of catalyst A under nitrogen, 11.34 g (94mmol) of N,N-dimethylaniline are added at 50° C. and stirring isperformed at this temperature for 4 h. 10.29 g (104 mmol) of copper(I)chloride are then added at 50° C. and stirring is performed at thistemperature for a further 8 h.

[0047] Catalyst Mix F

[0048] 232.0 g of 1,4-dichloro-2-butene are placed in the apparatusdescribed in the production of catalyst A under nitrogen, 15.84 g (94mmol) of diphenylamine are added at 50° C. and stirring is performed atthis temperature for 4 h. 10.29 g (104 mmol) of copper(I) chloride arethen added at 50° C. and stirring is performed at this temperature for afurther 8 h.

[0049] Catalyst Mix G

[0050] 232.0 g of 1,4-dichloro-2-butene are placed in the apparatusdescribed in the production of catalyst A under nitrogen, 10.52 g (104mmol) of triethylamine are added at 50° C. and stirring is performed atthis temperature for 4 h. 10.29 g (104 mmol) of copper(I) chloride arethen added at 50° C. and stirring is performed at this temperature for afurther 8 h.

[0051] Catalyst Mix H

[0052] 232.0 g of 1,4-dichloro-2-butene are placed in the apparatusdescribed in the production of catalyst A under nitrogen, 9.47 g (94mmol) of triethylamine are added at 50° C. and stirring is performed atthis temperature for 4 h. 10.29 g (104 mmol) of copper(I) chloride arethen added at 50° C. and stirring is performed at this temperature for afurther 8 h.

[0053] Catalyst Mix I

[0054] 232.0 g of 1,4-dichloro-2-butene are placed in the apparatusdescribed in the production of catalyst A under nitrogen, 7.37 g (73mmol) of triethylamine are added at 50° C. and stirring is performed atthis temperature for 4 h. 10.29 g (104 mmol) of copper(I) chloride arethen added at 50° C. and stirring is performed at this temperature for afurther 8 h.

[0055] Performing the Isomerization Reactions

Example 1

[0056] Under nitrogen, 240.0 g of 1,4-dichloro-2-butene are placed in a500 ml round-bottom flask with an internal thermometer, reflux condenserand pressure relief valve, 84.0 g of the catalyst mix A obtained at roomtemperature are added at 130° C. so that, with vigorous stirring, a mixtemperature of 150° C. is established, and stirring is performed at thistemperature for 90 min.

[0057] During the reaction period, samples are taken at fixed intervalsand investigated by gas chromatography for their content of3,4-dichloro-1-butene, cis-1,4-dichloro-2-butene,trans-1,4-dichloro-2-butene and any by-products formed, such as1-chloroprene. The starting point of the reaction is fixed as the end ofthe addition of the catalyst mix. Samples of approx. 2 ml in volume eachare taken at the starting point and after 5, 15, 30 and 90 minutes.

Example 2

[0058] 240.0 g of 1,4-dichloro-2-butene are placed in the test set-updescribed in example 1, 84.0 g of the catalyst mix B are added at 130°C. so that a mix temperature of 105° C. is established, and stirring isperformed at this temperature for 90 min. The timing, sampling andinvestigation of the samples are as explained in example 1.

Example 3

[0059] 240.0 g of 1,4-dichloro-2-butene are placed in the test set-updescribed in example 1, 84.0 g of the catalyst mixture C are added at130° C. so that a mix temperature of 150° C. is established, andstirring is performed at this temperature for 90 min. The timing,sampling and investigation of the samples are as explained in example 1.

Example 4

[0060] 240.0 g of 1,4-dichloro-2-butene are placed in the test set-updescribed in example 1, 84.0 g of the catalyst mix D are added at 130°C. so that a mix temperature of 105° C. is established, and stirring isperformed at this temperature for 90 min. The timing, sampling andinvestigation of the samples are as explained in example 1.

Example 5

[0061] 240.0 g of 1,4-dichloro-2-butene are placed in the test set-updescribed in example 1, 84.0 g of the catalyst mix E are added at 130°C. so that a mix temperature of 105° C. is established, and stirring isperformed at this temperature for 90 min. The timing, sampling andinvestigation of the samples are as explained in example 1.

Example 6

[0062] 240.0 g of 1,4-dichloro-2-butene are placed in the test set-updescribed in example 1, 84.0 g of the catalyst mix F are added at 130°C. so that a mix temperature of 105° C. is established, and stirring isperformed at this temperature for 90 min. The timing, sampling andinvestigation of the samples are as explained in example 1.

Example 7

[0063] 240.0 g of 1,4-dichloro-2-butene are placed in the test set-updescribed in example 1, 84.0 g of the catalyst mix G are added at 130°C. so that a mix temperature of 105° C. is established, and stirring isperformed at this temperature for 90 min. The timing, sampling andinvestigation of the samples are as explained in example 1.

Example 8

[0064] 240.0 g of 1,4-dichloro-2-butene are placed in the test set-updescribed in example 1, 84.0 g of the catalyst mix H are added at 130°C. so that a mix temperature of 105° C. is established, and stirring isperformed at this temperature for 90 min. The timing, sampling andinvestigation of the samples are as explained in example 1.

Example 9

[0065] 240.0 g of 1,4-dichloro-2-butene are placed in the test set-updescribed in example 1, 84.0 g of the catalyst mix I are added at 130°C. so that a mix temperature of 150° C. is established, and stirring isperformed at this temperature for 90 min. The timing, sampling andinvestigation of the samples are as explained in example 1.

Example 10

[0066] 240.0 g of 1,4-dichloro-2-butene are placed in the test set-updescribed in example 1, 84.0 g of the catalyst mix H are added at 165°C. so that a mix temperature of 130° C. is established, and stirring isperformed at this temperature for 90 min. The timing, sampling andinvestigation of the samples are as explained in example 1. MolarCatalyst mix ratio Content [%] Copper Copper Temperature3,4-dichloro-1-butene 1-chloroprene Example salt Base salt/base [° C.] 0min 5 min 15 min 30 min 90 min 90 min 1 A CuCl Aniline 1:1 105 6.9913.72 17.40 18.78 20.40 0.21 2 B CuCl Aniline 1:0.9 105 8.17 14.54 17.6219.40 21.58 0.52 3 C CuCl Aniline 1:0.8 105 9.20 13.26 16.77 19.84 21.160.43 4 D CuCl Aniline 1:0.7 105 6.86 13.15 17.98 20.87 21.18 0.29 5 ECuCl N,N-dimethyl- 1:0.9 105 7.45 13.6 16.08 17.27 19.38 n.d. aniline 6F CuCl Diphenylamine 1:0.9 105 8.24 11.01 15.75 18.96 19.09 0.34 7 GCuCl Triethylamine 1:1 105 7.01 7.58  9.58 11.89 16.05 n.d. 8 H CuClTriethylamine 1:0.9 105 8.40 14.36 16.77 16.89 17.06 0.93 9 I CuClTriethylamine 1:0.7 105 9.19 12.82 13.61 13.76 14.37 n.d. 10 H CuClTriethylamine 1:0.9 130 9.54 15.47 n.d. 17.82 18.13 2.73

[0067] Although the invention has been described in detail in theforegoing for the purpose of illustration, it is to be understood thatsuch detail is solely for that purpose and that variations can be madetherein by those skilled in the art without departing from the spiritand scope of the invention except as it may be limited by the claims.

What is claimed is:
 1. A composition producible by mixing an aromaticamine or several aromatic amines of the general formula I,

Wherein R¹ to R⁷, independently of one another, denote H, C₁ to C₁₂alkyl, C₅ to C₈ cycloalkyl, C₆ to C₁₄ aryl, alkylaryl, arylalkyl, withtwo adjacent groups together optionally forming saturated or unsaturatedC₃ to C₁₄ cycles, or —SiR⁸R⁹R¹⁰, wherein R⁸ to R¹⁰, independently of oneanother, can represent C₁ to C₄ alkyl, C₅ to C₈ cycloalkyl or C₆ to C₁₄aryl, with an anhydrous copper salt CuX_(n), wherein n=1 or 2 andX=halide, sulfate, acetate, acetylacetonate, naphthenate, or a mixtureof two or more of these copper salts.
 2. A composition according toclaim 1, wherein aniline, N,N-dimethylaniline, p-toluidine or mixturesof 2 or 3 of these components are used as the amine.
 3. A compositionaccording to claim 1, wherein the molar ratio of the two componentscopper salt/copper salts to aromatic amine/amines is in the range of1:0.5 to 1.5.
 4. A composition according to claim 1, wherein theconcentration of the components copper salt/copper salts and aromaticamine/amines is in the range of 10⁻³ to 1 mol/l.
 5. A catalystcomprising a composition producible by mixing an aromatic amine orseveral aromatic amines of the general formula I,

Wherein R¹ to R⁷, independently of one another, denote H, C₁ to C₁₂alkyl, C₅ to C₈ cycloalkyl, C₆ to C₁₄ aryl, alkylaryl, arylalkyl, withtwo adjacent groups together optionally forming saturated or unsaturatedC₃ to C₁₄ cycles, or —SiR⁸R⁹R¹⁰, wherein R⁸ to R¹⁰, independently of oneanother, can represent C₁ to C₄ alkyl, C₅ to C₈ cycloalkyl or C₆ to C₁₄aryl, with an anhydrous copper salt CuX_(n), wherein n=1 or 2 andX=halide, sulfate, acetate, acetylacetonate, naphthenate, or a mixtureof two or more of these copper salts.
 6. A process for the isomerizationof 1,4-dichloro-2-butene to 3,4-dichloro-1-butene or of3,4-dichloro-1-butene to 1,4-dichloro-2-butene, comprising the step ofa) adding, at a temperature of 30 to 180° C., an aromatic amine orseveral aromatic amines of the general formula I,

 wherein R¹ to R⁷, independently of one another, denote H, C₁ to C₁₂alkyl, C₅ to C₈ cycloalkyl, C₆ to C₁₄ aryl, alkylaryl, arylalkyl, withtwo adjacent groups together optionally forming saturated or unsaturatedC₃ to C₁₄ cycles, or —SiR⁸R⁹R¹⁰, wherein R⁸ to R¹⁰, independently of oneanother, can represent C₁ to C₄ alkyl, C₅ to C₈ cycloalkyl or C₆ to C₁₄aryl, and an anhydrous copper salt CuX_(n), wherein n=1 or 2 andX=halide, sulfate, acetate, acetylacetonate, or a mixture of two or moreof these copper salts, to 1,4-dichloro-2-butene, 3,4-dichloro-1-buteneor a mixture thereof, b) allowing the reaction solution to react untilan equilibrium has become established between 1,4-dichloro-2-butene and3,4-dichloro-1-butene, c) continuously removing a mixture of1,4-dichloro-2-butene and 3,4-dichloro-1-butene and then separating bydistillation, d) feeding back the undesirable component from thedistillation performed in c) into the reaction system, e) andoptionally, simultaneously with c), feeding 1,4-dichloro-2-butene and/or3,4-dichloro-1-butene into the reaction system.
 7. A process accordingto claim 6, wherein the temperature in step a) is in the range of 50 to150° C.
 8. A process according to claim 6, wherein the reaction periodin step b) is in the range of 15 and 45 minutes.
 9. A process accordingto claim 6, wherein in step a), the composition of amines is used inconcentrations in the range of 10⁻¹ to 1 mole Cu/l in1,4-dichloro-2-butene and/or 3,4-dichloro-1-butene and this is added to1,4-dichloro-2-butene, 3,4-dichloro-1-butene or a mixture thereof.
 10. Aprocess for the production of a composition comprising the step ofmixing an aromatic amine or several aromatic amines of the generalformula I,

wherein R¹ to R⁷, independently of one another, denote H, C₁ to C₁₂alkyl, C₅ to C₈ cycloalkyl, C₆ to C₁₄ aryl, alkylaryl, arylalkyl, withtwo adjacent groups together optionally forming saturated or unsaturatedC₃ to C₁₄ cycles, or —SiR⁸R⁹R¹⁰, wherein R⁸ to R¹⁰, independently of oneanother, can represent C₁ to C₄ alkyl, C₅ to C₈ cycloalkyl or C₆ to C₁₄aryl, with an anhydrous copper salt CuX_(n), wherein n=1 or 2 andX=halide, sulfate, acetate, acetylacetonate, naphthenate, or a mixtureof two or more of these copper salts, wherein the individual componentsare mixed together.